BackgroundIncreasing numbers of rice farmers are adopting direct-seeding methods to save on costs associated with labor and transplanting. Successful seedling establishment in flooded conditions requires rapid coleoptile growth to ensure access to oxygen near the water surface. It is important that the natural variations in coleoptile growth of submerged rice plants are identified.ResultsColeoptile responses of submerged plants at the germination stage were analyzed in diverse rice accessions and recombinant inbred lines. Several genomic regions identified from a genome-wide association analysis were significantly associated with anaerobic germination, with many that corresponded to published quantitative trait locus (QTL) intervals. In the recombinant inbred line population derived from a cross between japonica and indica varieties, only one unique and strong signal explaining about 27 % of the phenotypic variation was detected. Distinct haplotypes associated with variations in coleoptile length were identified in diverse germplasm.ConclusionsWe demonstrated the value of combining genome-wide association analysis and biparental QTL mapping approaches to identify chromosomal regions regulating coleoptile elongation in submerged rice plants. The significant genomic regions detected in this study are potential candidates for incorporation into elite cultivars to improve seedling survival during anaerobic germination. Future studies that map the QTLs and investigate the effects and functions of candidate genes may lead to new rice varieties that can be used in direct-seeding systems.Electronic supplementary materialThe online version of this article (doi:10.1186/s12284-015-0072-3) contains supplementary material, which is available to authorized users.

The Diels–Alder reaction is a useful tool for generating functionalized chiral molecules through the concerted cycloaddition of dienes and dienophiles leading to six-membered rings. Traditionally, the selective predictions of the products rely heavily on consideration of the secondary orbital interactions that stabilize the endo pathway. However, there remain some basic examples defying this notion and produce the exo-isomer as major product. Here we systematically evaluated of the structural features driving exo selectivity in thermal normal-electron-demand Diels–Alder reactions. Substitution at the Cβ position and the size and electronegativity of the electron-withdrawing group of the dienophile are contributing factors. Experimental and computational studies both point toward the steric and electrostatic forces between the substituents in both the diene and the dienophile that increase the likelihood of the exo pathway. For these substrates, the dominance of the endo pathway is reduced by transition state distortions and poor structural alignments of the reacting partners. We also noted the tilt of the dienophile with respect to the diene causing steric strain on the functionalities at the more advanced bond forming carbon-carbon position of the endo transition state. Insights into such factors may benefit synthetic planning and asserting control over this important named reaction.

A new pixel circuit using low-temperature polycrystalline-silicon (LTPS) thin-film transistors for Active Matrix Organic Light Emitting Diodes (AMOLEDs) is presented. The proposed current programming circuit without charging time problem at low gray level compensates for the threshold voltage variation of TFT as well as OLED luminance decay. The simulation results demonstrate driving current of this circuit is independent of the variation of TFT and maintain luminance for long term operation.

A new current scaling pixel circuit using three low-temperature polycrystalline-silicon (LTPS) thin-film transistors (TFTs) for Active Matrix Organic Light Emitting Diodes (AMOLEDs) is presented. The proposed circuit with simplified components can enhance the aperture ratio, accelerate the pixel programming time, as well as compensate for the variations of TFT threshold voltage. P-7 / C.-L. LinFigure 5. Comparison of OLED current as functions of input data current for the proposed pixel circuit, current copy circuit, and the current mirror circuit with a mirroring factor of 5. P-7 / C.-L. Lin SID 2012 DIGEST • 1075